Electrolytic condenser



J. K. SPRAGUE ELECTROLYTIC CONDENSER Filed Oct. 8, 1930 Aug. 27, 1935.

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Patented Aug. 27, 1935 UNITED STATES PATENT OFFICE ELECTROLYTICCONDENSER JulianK. Swami meane aallgnln entl,

Quincy, Mala, aaaignor, by

to Spfll e Specialties zscwm.

My invention relates to electrolytic cells and more particularly toelectrolytic condensers provided with a plurality of electrodes.

I shall illustrate my invention as applied to electrolytic condensersused in filter circuits for smoothing rectified alternating current.However, my invention is not limited to such devices and suchapplication.

Electrolytic condensers are well-known in the art and are widely used asfilter condensers in radio sets. In such application, it is in manyinstances advantageous to combine two or more condensers in a singleunit. In doing so. the container and the electrolyte are as a rulecomman and the container generally constitutes the common negativeelectrode, while the other electrodes are connected to diiferentpositive potentials. However, the potential difierence between theindividual anodes may cause objectionable leakage between same. Methodsso far proposed to reduce or prevent such leakage have been only partlysuccessful, and as a rule also have the drawback of considerablyincreasing the resistance between the anodes and the cathode.

By supporting electrodes from opposite ends of a common container, Ihave succeeded in obtaining multiple-electrode condensers which show no,or only a negligible amount of leakage between the anodes even if theyare connected to voltages of greatly differing values. At the same time,such condensers possess a relatively small resistance between the anodeand the cathode.

At the same time, these condensers are compact, simple to manufactureand very convenient for electrical connection.

Further advantages will appear as the specification progresses.

The single drawing, which iorms part of this specification, is a sideelevation partly in section of an electrolytic condenser embodying myinvention.

The condenser comprises a cylindrical container 20 of copper or otherinert metal.

The container 20 which constitutes the cathode is provided with suitablecovers it and II of insulating material and contains a suitableelectrolyte it into which project two electrodes A and B supported bythe covers it and It respectively. The electrodes A and B which are ofaluminum or other film-forming metals constitute anodes of thecondenser, and may be of any suitable design; however, I prefer toprovide anodes of the type described in the copending applications of F.Desmond Sprague and R. U. Clark, Ser. No. 416,939 filed Dec. 2'7, 1929,Patent No. 1,958,682, and of Max Knab, Ser. No. 441,128 .of April 2,1930, which possess various advantages fully described in theseapplications.

Such an electrode, as shown in the drawing. consists of a tubularportion 8 provided with g helical corrugations which through a conicalportion 9 extend in a stem it; the portions 8,

9 and It being formed of a single piece of metal. The portion 9 isprovided with holes for the circulation of the electrolyte. The stem I0is 10 provided with a bevelled shoulder 2| beyond which the stem isreduced. The end of the stem i0 is threaded at ii and carries nuts l2and I2, which fasten the electrode to the cover and also serve asoutside electrical terminals lot the anode, as indicated at 24'.

The cover it is of insulating material and rests on a circular indent iiof the container 20, The cover it is provided with a nipple l3 having avent hole i9 to vent the gases developed durm ing operation of thedevice. The cover it and the nipple l8 may form an integral piece assuggested in the copending application of C. Shugg and P. Robinson, Ser.No. 451,029 of May 9, 1930, Patent No. 1,895,738. a

The top of the cover It is provided with a peripheral recess to receivea sealing gasket l1 and the free end of the container 28 is preferablyspun around the gasket. Sealing means are also provided between the stemIll and the cover ll in the form of two gaskets 22 and 22 which surroundthe stem and fit in a corresponding recess of the cover ll. When theelectrode is screwed against the cover ll, the stem-shoulder 2| pressesthe gaskets 22 and 23 against the 35 cover thereby providing a liquidand air-tight sealing between cover and stem.

The two covers it and H are of identical construction; a vent nipple llhowever is required only on one cover.

The anodes A and B will be of equal or different length, dependingwhether equal or different capacities are required in the diflerentsections of the filter circuit.

Between the container and the anodes, I prefer 45 to provide a thincylindrical insulation it which prevents mechanical contact between theanode and the cathode, but which insulation is provided withperforations 25 to permit free circulation of the electrolyte and thusinsure that the resistance between the anodes and the cathode is keptlow.

A circular baille plate 24 of insulating material is inserted betweenthe anodes A and B, and u for It should be also well understood thatinstead,

of a single anode, a plurality ofanodes may be supported from eitherside of the container.

Various other modifications are possible without departing from thespirit of myfinvention. I do not wish, therefore, to be limited tothespecific embodiment of my invention, but desire the appended claims tobe construed as broad as permissible in view of the priorart.

I claim: 3

1. In an electrolytic condenser in combination a container forming thecathode, an electrolyte within said container and two anodes immergingin the electrolyte said anodes being supported from opposite ends of thecontainer and a separator between the anodes separating those portionsof the electrolyte in which the respective anodes immerge.

2. In an electrolytic condenser, a substantially cylindrical cathode, aplurality of substantially cylindrical anodes placed within said cathodeand in axial alignment with each other, and an insulating member betweensaid anodes and the cathode.

3. In an electrolytic condenser in combination a cathode container, anelectrolyte within said container, two filmed electrodes supported fromthe two ends of the container and immerging in the electrolyte and meansto isolate the electrolyte between the two electrodes.

4. In an electrolytic condenser in combination a cylindrical containerforming the cathode, two cylindrical anodes placed within said cathodeand in axial alignment with each other, an insulating member betweensaid anodes and the cathode, means to decrease the electrical resistancebetween the anodes and the cathode, and means to increase the resistancebetween the two anodes.

5. In an electrolytic condenser, a substantially cylindrical containerforming the cathode of the condenser, an electrolyte in said container,two substantially cylindrical anodes placed within said container and inaxial alignment with each other, a cylinder of insulating materialbetween said anodes and said cathode, and an insulating baille platelocated between the two anodes and within said insulating cylinder.

6. In an electrolytic condenser, two substantially cylindrical anodesdisposed in axial alignment and a cathode surrounding the two anodes,the effective height of the cathode being substantially equal to the sumof the eii'ective height of the two anodes.

7. In an electrolytic condenser, comprising a cylindrical cathodecontainer provided on both ends with covers of insulating material, eachcover supporting a corrugated tubular anode, the overall diameter ofsaid anodes being only slightly less than the inside diameter of thecontainer.

8. In a multi-section electrolytic condenser, the sections of which havediiferent capacities and are connected to different potentials, in combination a plurality of substantially cylindrical anodes in axialalignment with each other, said anodes having identical outside diameterand different length with a common cylindrical cathode surrounding saidanodes and having an inside diameter only slightly in excess of theoutside diameter of the anodes.

9. In an electrolytic condenser, having two anodes, a substantiallycylindrical cathode container, and an electrolyte therein, a member ofinsulating material on each end of the container to close the containerand support one anode. each anode comprising a substantially cylindricalportion immersed in the electrolyte and integral therewith a portionimmerging from the electrolyte and projecting through the respectivemember of insulating material to constitute an outside terminal for thecondenser.

10. An electrolytic condenser comprising a substantially cylindricalmetallic cathode conin, two elongated anodes insulatingly supported fromthe opposite ends of the container and immerging in said electrolyte andmeans to substantially separate the electrolyte between the two anodes.

13. An electrolytic condenser comprising a:;

cathode container and an electrolyte, and two filmed electrodesprojecting in said electrolyte from opposite ends of said container,said electrodes being substantially in axial alignment with each other.

14. An electrolytic condenser comprising a container forming thecathode, an electrolyte and two anodes projecting in said electrolytefrom opposite ends of the container and a member interposed'between theanodes to substantially separate that portion of the electrolyte inwhich one anode immerges from that portion of the electrolyte in whichthe other anode immerges.

15. An electrolytic condenser comprising a cathode container, aliquid-electrolyte and two elongated filmed electrodes projecting insaid electrolyte from opposite ends of the container and being invertical alignment with each other and closely spaced to each other endto end, and a member between the ends of said electrodes to preventdirect communication of the electrolyte between said two ends.

16. An electrolytic condenser comprising a metal container and a liquidelectrolyte in said container, a partition dividing said electrolyteinto two portions and filmed electrodes immerging in said portions ofthe electrolyte from opposite ends of said container, said electrodesbeing insulatingly supported from saidcan tainer.

17. An electrolytic condenser comprising :1. metal container forming acathode, an electrolyte in said container and two anodes immerging insaid electrolyte from opposite ends thereof, said anodes being disposedin axial alignment and being closely surrounded by said container, aperforated separator between said anodes and said container and a baiiieplate between said anodes to prevent direct communication or theelectrolyte between same.

18. An electrolytic condenser comprising a substantially cylindricalmetal container forming a cathode and a liquid electrolyte in saidcontainer, two anodes insuiatingly supported from opposite cathodecontainer and two filmed electrodes supported from the opposite ends ofsaid container, and a liquid electrolyte substantially filling saidcontainer but shiftable therein, said electrolyte surrounding saidelectrodes.

20. In an electrolytic condenser, a substantially cylindricalelectrolyte container having top and bottom walls and having the bodyportion thereof of conducting material adapted to serve as one terminalof the condenser, a pair of separate electrodes immersed in saidelectrolyte in superposed spaced relationship and adapted to serve ascondenser terminals complementary to said firstnamed terminal, aconducting rod supporting one of said electrodes from above andextending out 01' the container through said top wall, a conducting rodsupporting the other electrode from underneath and extending out of thecontainer through said bottom wall, and means for insulating said rodsat said top and bottom walls, respectively, from the conductive bodyportion of the container.

21. In an electrolytic condenser, a substantially cylindricalelectrolyte container of conductive material adapted to serve as onecondenser electrode and having top and bottom walls, a pair of mutuallyindependent electrodes immersed in said electrolyte in superposed spacedrelationship and individually complementary to said container, aconducting rod supporting one of said electrodes from above andextending out of the container through said top wall, a conducting rodsupporting the other of said electrodes from underneath and extendingout of the container through said bottom wall, and means for making thejoints between said rods and the top and bottom wall liquid-tight.

22. In an electrolytic condenser, a substantially cylindricalelectrolyte container having top and bottom walls and having the bodyportion thereof of conducting material adapted to serve as one terminalof the condenser, a pair of separate electrodes immersed in saidelectrolyte in superposed spaced relationship and adapted to serve ascondenser terminals complementary to said first-named terminal, aconducting rod supporting one or said electrodes from above and extending out of the container through said top wall, a conducting rodsupporting the other electrode from underneath and extending out of thecontainer through said bottom wall, means for insulating said rods atsaid top and bottom walls, respectively, from the body portion of thecontainer, and a partition within the container between said electrodes.

23. In an electrolytic condenser, a substantially cylindricalelectrolyte container having top and bottom walls and having the bodyportion thereof of conducting material adapted to serve as one terminalof the condenser, a pair of substantially cylindrical electrodesimmersed in said electrolyte in superposed, axially-aligned, spacedrelationship, said electrodes being adapted to serve as condenserterminals complementary to said first-named terminal, a conducting rodsupporting the upper electrode from above and extendin out of thecontainer through said top wall, means for insulating said rod at saidtop wall from the body portion of the container, a second conducting rodaligned with the first and supporting the lower electrode fromunderneath and extending out of the container through the bottom wallthereof, means for insulating said lower rod at said bottom wall fromthe body portionot the container, and means for making the joint betweensaid lower rod and said bottom wall liquidtight.

24. An electrolytic condenser comprising a cathode container and aliquid electrolyte and filmed anodes therein, said anodes being in axialalignment with each other and having a large surface area, saidcontainer closely surrounding said anodes and conforming in its shape tothe contour surface of said anodes, said anodes being adapted to beconnected to diilerent electrical potentials and projecting into saidelectrolyte from the opposite ends of the container.

25. An electrolytic condenser comprising a cathode container, anelectrolyte, and two elongated fllming anodes projecting into saidelectrolytefrom opposite ends of the container and being in verticalalignment with each other, and means to considerably increase theelectrical resistance between said electrodes.

JULIAN K. SPRAG

